Abstract: At present, Vertical components gravity is measured and solved in a local frame with the E tv s correction in airborne scalar gravimetry systems. The classic method ignores the vertical deflection effect. In this study, an improved formula is presented and the gravity measurement problem is solved in a quasi-inertial frame. The modified method improves the classical formulas for scalar systems theoretically, avoiding computing Eötvös and other approximations. The method was validated using a numerical test. The results show that the unnecessary approximations found in the traditional method will cause sub-mGal level errors. However, these errors can become almost negligible after applying a low-pass fillter with cut-off frequency at less than 1/60 s. In addition to this theoretical advantage, the modified method can acquire mGal-level horizontal gravity estimates through a precise data processing.